The invention relates to a method for operating a hybrid drive device having a first drive aggregate and a second drive aggregate, wherein in a first operating mode a drive torque of the hybrid drive device is solely generated by the first drive device and in a second operating mode jointly by the first drive aggregate and the second drive aggregate, and wherein when switching from the first operating mode to the second operating mode an actual rotational speed of the second drive aggregate is adjusted to a target rotational speed. The invention also relates to a hybrid drive device.
The hybrid drive device has at least two drive aggregates, i.e., the first drive aggregate and the second drive aggregate. As drive aggregates, electric machines, internal combustion engines or the like can be provided in any combination. For example the first drive aggregate can be an electric machine and the second drive aggregate an internal combustion engine. In the first operating mode the drive torque is solely provided by the first drive aggregate. This means that the second drive aggregate is deactivated and/or decoupled from the first drive aggregate. Correspondingly no operative connection is present between the first drive aggregate and the second drive aggregate. When the first drive aggregate is configured as electric machine, the hybrid drive device is operated purely electrically in the first operating mode, in particular the motor vehicle which has the hybrid drive is driven purely electrically.
In the second operating mode on the other hand the first drive aggregate and the second drive aggregate jointly generate the drive torque. This means that the first drive aggregate as well as the second drive aggregate each provide a portion of the drive torque that is different from zero. Usually however the second drive aggregate is deactivated in the first operating mode or has at least only a low rotational speed, in particular a lower rotational speed than the first drive aggregate. It is thus necessary to adjust the actual rotational speed of the second drive aggregate to the target rotational speed when switching from the first operating mode to the second operating mode. The target rotational speed is preferably a rotational speed at which the second drive aggregate has to be operated in order to be coupled with the first drive aggregate, in particular without sacrificing comfort. The target rotational speed for example corresponds to the actual rotational speed of the first drive aggregate, in particular taking a transmission ratio of a transmission that may be arranged between the first drive aggregate and the second drive aggregate into account.
From the state-of-the-art for example the patent document DE 10 2008 002 383 A1 is known which describes a method for controlling a hybrid drivetrain of a motor vehicle. Further a method for electronic control of the rotational speed of at least one drive motor of a motor vehicle is described in reference DE 10 2012 018 222 A1. Hereby the rotational speed differential between a predetermined target rotational speed and an actual rotational speed of the drive motor and the rotational speed gradient differential according to value and direction and/or the actual and/or target rotational speed gradient according to value and direction are used for determining at least one control parameter which influences the feedback control of the rotational speed in a feedback control model, wherein the feedback control model determines a P-component and an I-component, wherein prior to adding up the components a correction factor is applied to the determined P-component, which factor is dependent on the state of the drive motor. Also known from the state-of-the-art further are the references DE 10 2012 003 020 A1, DE 11 2010 005 907 T5 and DE 11 2010 000 430 T5.